Suntour Chainline and chain question

[79stef]

Having stalled on my build I have now reached a stage of fitting the crankset and setting up the drive.

I'm using Suntour XC Microdrive gear. My seat tube measures 35mm and I currently have a 115mm bottom bracket fitted. This makes the chainline to the middle ring 47.5mm.

Can anyone with experience setting up Suntour Microdrive stuff tell me whether 47.5mm is OK or whether I should change the BB to aim for 50mm?

Also for a 3x7 set up, what (modern) chain should I go for? I've heard I need a thinner chain, so perhaps 9 speed KMC?

 

[FluffyChicken]

47.5mm is the default chainline for 7 and 8 speed setups (Suntour, Shimano.. for a triple ring crank)
That's perfect if everything works. I.e your front mech shifts across it all, the rings/cranks don’t hit amything.

Any 7/8/9 speed chain is fine.

I'd probably be looking for an KMC X8 or SRAM PC850 or other brand chain in the range that looks nice and is cheap enough. These are 8 speed targeted.
I use a few alternative brands now.

 

[79stef]

Thank you @FluffyChicken
I thought you might be the man to know the answer to this one!
I'm time constrained at the moment but will post updates in my build thread when I get around to sorting it.

On a separate note, with regards the cassette.. in light of the fact that the lock rings (cogs) are notorious for getting seized on after a few rides, would copper slip or any other product be recommended, or do I just have to live with it?

 

[Tootyred]

I always go Sram 8 speed. Just pick the finish you like from bright to dull....prices go with the shine level!

You can copper slip them, but it will make little difference. Its not corrosion normally, just actual force holding them. But it might help in the future.

 

[79stef]

Thanks @Tootyred. My LBS stocks SRAM chains, so I'll go for that.
If no harm is done by adding copper slip, then I will give it a go

 

[FluffyChicken]

The problem, as with all the screw on bottom cog style, is that as you pedal or change into that gear you give it a quicker hammer with the chain and screw it on a bit more.
And there are two cogs doing it in the MD system.

 

[79stef]

The problem, as with all the screw on bottom cog style, is that as you pedal or change into that gear you give it a quicker hammer with the chain and screw it on a bit more.
And there are two cogs doing it in the MD system.

Yes, not the best design!